How much does an ADU cost to build in Northern Utah? It’s the first question almost every homeowner asks when they start thinking about adding an accessory dwelling unit to their property, and it deserves an honest answer rather than a vague range that doesn’t help you plan. ADU costs vary significantly depending on the type of unit, the complexity of the build, and what’s already on your property. Here’s a realistic breakdown of what to expect in Cache Valley in 2026.
Why ADUs Are Growing in Cache Valley
Before we get into numbers, it’s worth understanding why ADU construction is one of the fastest growing conversations we’re having with homeowners in Northern Utah right now.
Property prices across Cache Valley have climbed significantly over the last several years. Building on land you already own is increasingly more affordable than buying new land and starting from scratch. You already have the property. You already have utilities running to the site. And the structure you build can generate rental income, house a family member, or add significant long-term equity to your home.
We’re fielding calls about ADUs just about every day now. It has stopped being a niche conversation and is becoming a standard option for homeowners across Logan, North Logan, Providence, Smithfield, and surrounding communities.
ADU Cost Ranges in Northern Utah
ADU costs in Utah in 2026 vary widely depending on what type you’re building. Here’s an honest breakdown by type.
Garage conversions and basement conversions are typically the most accessible entry point. Because the main structure already exists, you’re not starting from scratch on the exterior shell.
These projects typically run $75,000 to $170,000 depending on the level of finish, what’s required to make the space legally habitable, and how much utility work is involved. A basement ADU conversion that already has plumbing roughed in will cost significantly less than a garage conversion that needs everything run from scratch.
Attached ADUs, built directly onto your existing home and sharing a wall and sometimes utilities, typically run $150,000 to $250,000. Because attached units share some infrastructure with the main home, they can be somewhat less expensive than a fully detached build. However, the complexity of tying into an existing structure can offset some of those savings depending on what’s involved. The choice between the two is worth its own conversation, which we had in attached versus detached ADUs in Utah.
Detached ADUs (fully standalone structures with their own foundation, framing, siding, roofing, and utility connections) are where costs climb the most. Expect $150,000 on the low end and $400,000 and above for larger or more complex builds. In Cache Valley, a realistic budget for a well-built, fully permitted detached ADU is in the $150,000 to $200,000 range for a functional mid-range unit.
Working out the number for your own build
Total ranges only take you so far, because the size you have in mind moves everything. Costing it per square foot lets you sanity check a quote against your actual plan. Across the market in 2026, attached units run roughly $125 to $225 per square foot and detached units $150 to $250. A unit built above a garage runs higher, commonly $200 to $500 and up, because you are adding structure and access on top of an existing building. Conversions run far lower, with basement conversions around $50 to $100 per square foot and garage conversions anywhere from $50 to $200 depending on what has to be added.
Those are market figures rather than a Salt to Summit price list, and they are worth using the way you would use any benchmark. Multiply by the square footage you actually want, add utilities and soft costs on top, and you have a number you can hold a bid up against. Labor accounts for something like forty to sixty percent of an ADU build, which is why quotes vary more between contractors on this kind of work than on a straightforward remodel.
What Drives ADU Costs Higher Than Expected
Here’s where most homeowners get surprised. An ADU is essentially new construction rather than a basement finish or a kitchen remodel, a fully independent living space built from the ground up. That means everything that goes into building a home applies here.
Foundation. Framing. Siding. Roofing. Insulation. HVAC. Electrical. Plumbing. Kitchen. Bathroom. Flooring. Finishes. All of it adds up the same way it does in any new build.
But the cost that surprises people most is utilities. Running water, sewer, and electrical from the street or the main house to your ADU can cost $8,000 to $18,000 just for the utility connections alone, before a single wall goes up. If your lot has rocky soil, which is common in parts of Cache Valley, excavation costs can push that number higher.
Then there are the soft costs. Architectural drawings or engineered plans are required for the permit process in most Cache Valley municipalities. That’s typically an additional $2,500 to $4,500 on top of construction costs. Factor it in from the start.
What has to be there for it to count as an ADU
A common and expensive misunderstanding is that a finished room with a bathroom qualifies. It does not. Logan defines an accessory dwelling unit as a complete secondary residential unit, and complete means a living or sleeping space, a kitchen, a bathroom and shower facilities. A finished basement without a kitchen is a finished basement, however nice it is.
That matters for your budget, because the kitchen and the second bathroom are usually the difference between a conversion that pencils and one that does not. It matters for the permit as well. Logan requires a Declaration of Owner Occupancy alongside the ADU application, and not every property is eligible, so the Planning Division check on eligibility belongs at the start of your process rather than after you have drawn plans. We cover that side in detail in what permits you need to build an ADU in Cache Valley.
What a Low Bid Actually Means
I want to be direct about this because it matters.
If a contractor tells you they can build a full permitted ADU for $60,000 in 2026, they are cutting corners somewhere. Permits. Fire blocking. Waterproofing. Proper utility connections. None of those are optional line items. They are what make an ADU legal, safe, and insurable.
A realistic bid in Cache Valley reflects the real cost of building something that will pass inspection, hold up over time, and actually add value to your property. If a number sounds too good to be true, ask specifically what’s included and what the permit and inspection process looks like. The answer will tell you everything. Request an estimate from a licensed contractor who will give you honest numbers from the start.
The Case for Building an ADU Right Now
Despite the upfront cost, ADUs are one of the most compelling investments a Cache Valley homeowner can make in this market.
A well-built, fully permitted ADU adds real appraised value, typically in the range of twenty to thirty five percent of the property value, which we broke down properly in whether building an ADU increases your home value. Rental rates for ADUs in Utah in 2026 are running $1,200 to $2,500 per month depending on size, location, and finish level. That’s income that can cover a significant portion of your mortgage or simply build long-term financial security.
And beyond the financial case (multigenerational living, housing for aging parents, a space for adult children returning home) the flexibility an ADU provides is something a standard home addition simply can’t replicate.
